This program will attempt to develop a transdermal system capable of delivering enough levonorgestrel in 24 hours to provide emergency postcoital contraception as effective as currently approved oral methods, but with greater convenience and fewer side effects. The Phase I feasibility study will seek to confirm and improve on levonorgestrel fluxes of observed by BIOTEK during past work on contraceptive and anti- osteoporosis patches. Such fluxes would allow a patch to deliver more levonorgestrel. PROPOSED COMMERCIAL APPLICATION Oral medications now available for the emergency prevention of unwanted pregnancies cause very unpleasant side effects, which transdermal delivery is less likely to provoke. The development of such a product involves demonstrating and implementing a very high transdermal flux for levonorgestrel, a highly insoluble steroid. This should open the door to other new products in such areas as hormone replacement therapy, contraception, prevention of osteoporosis, and treatment of endocrine disorders.